Rolling mills



March 24, 1970 D. s'ruass 3,

ROLLING MILLS Filed Nov. 15, 1966 3 Sheets-Sheet 1 INVENTOR DENNIS STUBBS ORNEY March 24, 1970 D. STUBBS 3,

ROLLING MILLS Filed Nov. 15, 1966 3 Sheets-Sheet 3 Fla INVENTOR DENNIS STUBBS ATTORNEY United States Patent 3,501,936 ROLLING MILLS Dennis Stubbs, Sheflield, England, assignor to Davy and United Engineering Company Limited, Sheffield, England Filed Nov. 15, 1966, Ser. No. 594,478 Claims priority, application Great Britain, Nov. 15, 1965, 48,335/ 65 Int. Cl. B21b 31/24 US. Cl. 72-243 13 Claims ABSTRACT OF THE DISCLOSURE The invention is concerned with that type of rolling mill comprising a pair of spaced housings, each having therein a housing window and a pair of roll assemblies carried in chocks which are slidably arranged in the windows, The roll assemblies are spaced apart by spacing devices, each of which acts between the chocks of the two roll assemblies and each of which is adjustable in effective length to vary the separation of the chocks. Each of the spacing devices is mounted on and carried by its housing and can slide bodily on the housing in the direction of chock movement so as to accommodate itself to changes in the median plane between the chocks.

This invention relates to rolling mills and is particularly concerned with a rolling mill of the type in which there are two roll assemblies, each comprising a work roll in the case of a two-high mill, or a work roll and back-up roll in the case of a four-high mill, with the appropriate bearing chocks, the two roll assemblies being mounted in housings and spaced apart from one another by adjustable spacing devices; the roll assemblies are loaded together, for example by hydraulic cylinders or screws acting between the housings and the roll assem blies.

In previously suggested rolling mills of the type described, the spacing devices take the form of adjustable screws carried in the chocks of one of the roll assemblies and engaging against the other roll assembly. For example, in one such arrangement, the upper back-up chocks are specially designed with threaded passages, in which are located the screws, which engage the upper faces of the lower back-up chocks. In another suggestion, the screws are similarly mounted in the upper work roll chocks and bear against the lower work roll chocks; in this latter case, both the upper work roll chocks and the upper back-up roll chocks require to be specially designed, since the drive to the screws passes through shafts rotatably located in the upper back-up roll chocks.

In accordance with one aspect of the present invention, a rolling mill comprising a pair of spaced housings, each having therein a housing window, and a pair of roll assemblies carried in chocks slidably arranged in the windows, has screw jack spacing devices acting between the chocks of the two roll assemblies, each such spacing device being mounted on the respective housing for movement relative to the housing in the direction of chock movement.

Each of the spacing devices may be a telescopic screw jack supported between the roll assemblies by the housing. Alternatively, each screw may be rotatably mounted in a block slidably carried in the housing and engaging one of the roll assemblies, the screw engaging the other roll assembly.

According to a second aspect of the invention, a fourhigh rolling mill comprises a pair of spaced housings each having therein a housing window, and, for each housing, a pair of back-up roll chocks slidably mounted in the housing window, a pair of work roll chocks having transverse dimensions substantially less than the back-up roll chocks a pair of mechanical spacing devices located in the window, one at each side of the work roll chocks, engaging against the back-up roll chocks, and mounted on the housing for movement in the direction of chock movement.

The invention will be more readily understood by way of example from the following description of rolling mills in accordance therewith, reference being made to the accompanying drawings, in which:

FIGURE 1 is an end view of one of the housings of the mill, and

FIGURE 2 is a vertical section through the chocks of the same housing FIGURE 3 is an end view of a second form of mill with parts in section, and

FIGURE 4 is a section on the line IV-IV of FIG- URE 3.

While the following description will be confined to one of the housings of the mill, it will be appreciated that the other housing is basically similar.

Referring to FIGURES 1 and 2, the housing 12 has a housing window 13, in which slide the chocks 14, 15 of the upper and lower back-up rolls 16, 17 respectively. The chocks are held against movement in the axial direction of the rolls by keeper plates 18.

The window 13 is enlarged at 20 to receive insert blocks 21, 22 which are held in position by keys 23. These insert blocks 21, 22 have slide surfaces 24, between which the chocks 25, 26 of the upper and lower work rolls 27, 28 respectively slide and by which they are guided.

Each insert block 21, 22 has a vertical passage 30 passing through it. A sleeve 31 is secured in the bottom of each passage 30 and carries a screw 32, which is permitted to move axially but not rotationally by keys 33. The lower end of each screw 32 engages against a partspherical thrust block 34 carried in the lower back-up roll chock 15. A load cell 35 may be disposed between each thrust block 34 and the chock 15, for control purposes.

A nut, in the form of a hollow column 36, is threaded on to the upper part of each screw 32 and bears at its upper end against a thrust block 37 located in the lower surface of the upper back-up roll chock 14. Each nut 36 is splined to an encompassing worm wheel 38 carried by the insert block 21 or 22 and driven by a worm 40 carried by a shaft 41, extending parallel to the roll axes and terminating externally of the housing to be driven by an electric motor (not shown).

The upper back-up roll chock 14 engages against the top of the housing 12, a further load cell 42 being interposed, again for control purposes. The lower back-up roll chock 15 is engaged by a prestressing hydraulic rarn shown diagrammatically at 43 and carried in the lower part of the housing 12.

In operation, the roll assemblies are prestressed by the hydraulic ram 43, the separation of the back-up roll chocks being largely determined by the screws jacks constituted by the screws 32 and the column nuts 36. The spacing of the work rolls 27, 28 and hence the roll gap is adjusted by the screw jacks 32, 36, which are in turn adjusted by driving the shafts 41. These shafts turn the nuts 36 and therefore extend or collapse the screw jack. Each screw jack itself is capable of movement vertically as a whole, by virtue of the keys 33 and the splines between the nut 36 and the worm wheel 38. It will be perceived that. because the screw jacks 32, 36 are carried by the housing 12, through the insert blocks 21, 22, the back-up roll chocks 14 are of conventional form and do not require special machining to carry screws and the drives therefor.

For roll change purposes, each lower work roll chock 26 carries wheels 44 designed to run on rails 45 permanently mounted on the insert blocks 21, 22 and extending between the two housings. Also, the lower back-up roll chocks carry wheels 46 designed to run on rails 47 secured at the bottom of of the housing window 13 and also extending between the two housings. To remove the work rolls 27, 28 with their chocks, the lower back-up roll chocks 15 are first lowered, by operation of the screw jacks 32, 36 in order to open the roll gap. Packers are positioned between the work roll chocks 25, 26 and the pressure in the hydraulic work roll balance cylinders 48 is released to lower the upper work roll chock 27 onto the packers. Finally, the pressure in the hydraulic ram 43 is released, to lower the lower back-up roll chock 15, and thus the work rolls, until the wheels 44 engage the rails 45. The two work rolls with their chocks can then be run out of the mill on the rails 45, the upper back-up roll chock 14 meanwhile being supported on projections 50 of the housing 12.

A complete change of work and back-up rolls is effected by placing packers between each set of chocks, contracting the screw jacks, 32, 36 and the balance cylinders 48, so that the chocks are supported by the packers, lowering the hydraulic ram 43 until the Wheels 46 of the lower back-up roll chocks 15 rest on the rails 47, and finally running the full set of rolls and chocks out of the mill on the rails 47.

It will 'be appreciated that other forms of screw may be employed in place of the screw jacks 32, 36 provided that they are carried by the housing and are not driven through the back-up roll chocks. For example, insert blocks, similar to those shown at 21, 22 may be mounted in the housing 12 so as to be capable of limited vertical movement with respect to the housing. These insert blocks engage the upper surfaces of the lower back-up roll chocks 15 and carry, threaded therein, vertical screws which e11- gage the upper back-up roll chocks 14. The screws are driven through splined sleeves in normal manner, -in order to increase or decrease the separation of the back-up roll chocks. Of course, the rolls of the screws and the insert blocks may be reversed, the screws engaging the lower back-up roll chock and the insert blocks the upper back-up roll chocks.

In both the arrangement illustrated in the accompanying drawings and in the alternative above, both the construction of the upper back-up roll chocks is simplified and cheapened by the screw jacks being carried by the housing directly, and also roll change is facilitated for the same reason.

In the mill shown in FIGURES 3 and 4, wedges are used, in place of screw jacks to adjust the roll gap. In these figures, the arrangement of housings 12, chocks 14, 15, 25, 26 and rolls 16, 17, 27 and 28 is generally similar to that of FIGURES 1 and 2. In this case, however, the prestressing cylinder 60 of each housing is shown as mounted in the top of the housing window, the piston 61 engaging against the top of the upper back-up chock 14 of the respective housing. The bottom of each housing window carries a thrust pad 62 incorporating a load cell 63.

As before, there is a spacing device located at each side of the work roll chocks 25, 26 of each housing, the spacing devices occupying the spaces between the chocks 25, 26 and the sides of the windows. Each such spacing device comprises a box-like structure 64 which is mounted on the housing by guide plates 78 permitting the structure to slide freely on the face of the window, and which has a guide face 65 restraining the work-roll chocks 25, 26 against transverse movement while permitting them to move freely vertically. Two plungers 66, 67 extend downwardly and upwardly respectively from the structure 64 and engage the lower and upper back-up chocks 15, 14 respectively, through thrust pads 68, 70 and, in the case of lower plunger 66, a load cell 71.

At their inner ends, the plungers 66, 67 have wedge faces 72, 73 which engage the opposite faces of a double wedge member 74. This wedge member 74 is internally threaded and is carried on a threaded shaft 75, which projects out of the structure 64 to terminate in a gear 76 housed in an extension housing 77 carried by structure 64. Also mounted in the housing 77 is an electric or hydraulic motor (not shown) which is coupled to the gear 76. The four motors of the four spacing devices of the mill may be controlled to operate equally.

When the motor of any spacing device is actuated, the shaft 75 is rotated and causes the wedge member 74 to move transversely relative to the plungers 66, 67, the direction depending on the direction of drive of the motor. This wedge movement results in the plungers 66, 67 moving inwardly or outwardly relative to the structure 64 and, thus, a change in separation of back-up roll chocks 14, 15 and in the roll gap. As the spacing device is freely mounted for vertical movement relative to the housing, it can position itself appropriately between the back-up roll chocks, regardless of the roll gap required and of the relative wear of the rolls.

What is claimed is:

1. A rolling mill comprising a pair of spaced housings each having therein a housing window, a pair of roll assemblies carried in chocks slidably arranged in the windows and screw jack spacing devices acting between and engaging with the chocks of the two roll assemblies, each such spacing device having an adjustable length to vary the separation of the chocks, means for slidably mounting said spacing devices on the respective housings and within the windows of the housings for bodily movement relative to the housings in the direction of chock movement.

2. A four-high rolling mill comprising a pair of spaced housings each having therein a housing window, and, for each housing, a pair of back-up roll chocks slidably mounted in the housing window, a pair of work roll chocks having transverse dimensions substantially less than the back-up roll chocks, and a pair of mechanical spacing devices located in the window, one at each side of the work roll chocks, and engaging against both the back-up roll chocks, each spacing device having an adjustable length to vary the separation of the chocks, means for slidably mounting said spacing devices on the housings and within the windows of the housings for bodily movement relative to said housings in the direction of chock movement.

3. A rolling mill as claimed in claim 2 in which each spacing device is carried in a block secured in the housing and projecting into the window to form a sliding guide surface for the work roll chocks.

4. A rolling mill as claimed in claim 2 in which each spacing device is a screw jack.

5. A rolling mill as claimed in claim 3 in which each spacing device comprises a pair of co-operating threaded members located in a passage in the block, one being permitted to move longitudinally but not rotationally in the block and the other being so coupled to a rotary drive mechanism as to permit longitudinal movement relative thereto.

6. A rolling mill as claimed in claim 5 in which said other member is splined to a drive sleeve.

7. A rolling mill as claimed in claim 6 in which said one member is a piston which is partially threaded externally and mates with an internally threaded cylinder, which constitutes said other member.

8. A rolling mill as claimed in claim 2 in which there is a prestressing piston and cylinder carried in each housing at one end of the window and acting on the adjacent back-up roll chock.

9. A rolling mill as claimed in claim 3 in which the blocks carry inwardly projecting rails and the lower work roll chocks have wheels adapted to run on the rails for roll change purposes.

10. A rolling mill as claimed in claim 2 in which each spacing device includes a wedge arranged to adjust the effective length of the spacing device between the back-up roll chocks.

11. A rolling mill as claimed in claim 10 in which each spacing device comprises a box-like structure slidably mounted on the housing and projecting into the window to form a guide surface for the work roll chocks, the wedge being carried in the box-like structure and cooperating with a pair of force-transmitting members protruding from the structure and engaging the back-up roll chocks.

12. A rolling mill as claimed in claim 11 in which the wedge is threaded on a rotary shaft, the wedge surfaces engaging corresponding wedge surfaces on the force transmitting members.

13. A rolling mill comprising a pair of spaced housings each having therein a housing window, a pair of roll assemblies carried in chocks slidably arranged in the windows and screw jack spacing devices acting between the chocks of the two roll assemblies, each such spacing device having an adjustable length to vary the separation 6 of the chocks, means associated with each housing for mounting one of said spacing devices on each of said housings, said spacing device including two opposed movable members slidably carried by said mounting means for bodily movement relative to the housings in a direction of the chock movement.

References Cited UNITED STATES PATENTS 2,095,448 10/1937 McBane 72-245 2,363,656 11/1944 Dawson 72-237 3,247,697 4/ 1966 Cozzo 72-240 3,369,383 2/1968 Barnikel 72-245 FOREIGN PATENTS 955,164 4/1964 Great Britain.

MILTON J. MEHR, Primary Examiner 20 B. J. MUSTAIKIS, Assistant Examiner US. Cl. X.R. 72-238 

